This invention relates to a control for a plurality of air conditioning units installed in separate rooms of a multi-room building, and in particular, to a control specifically designed to prevent such units from continuing to operate over prolonged periods of time when the rooms are not occupied.
The recent energy shortage and increased energy costs has resulted in a new awareness that power consuming apparatus should only be operated when actually needed. That is to say, continuous operation of power consuming apparatus under conditions not actually requiring such operation, not only wastes energy but also results in unwarranted operating costs for such apparatus. For example, in multi-room buildings such as hotels and motels, wherein each room has its own air conditioning unit, the operation of any one air conditioning unit is only required when the room served by such one unit is occupied. When the room is not occupied, continuous operation of the air conditioning unit results in an undesired wastage of energy.
As used herein, the term air conditioning unit encompasses various types of air conditioning apparatus, utilizing electrically operated components. For example, the typical room air conditioning unit employs a mechanically operated refrigeration unit utilizing an electrically operated compressor motor and one or more fan motors. A fan coil unit includes an evaporator coil installed in the room and has an electrically operated fan to route room air thereover. Other similar types of electrically operated air conditioning units shall be included within the scope of the present invention.
An example of a prior patent which recognizes the same problem as that described hereinabove is disclosed in U.S. Pat. No. 4,060,123. In this patent, the occupancy status of each room is detected by suitable detector means, with the air conditioning unit being rendered inoperable when the room is unoccupied and automatically rendered operable when the room is occupied.
The energy saving control disclosed in the aforecited United States Patent is relatively complex when compared to the present invention.